Heatwaves are recognized as prolonged periods of excessively hot weather, which can have severe implications on human health, the environment, and the economy. With India’s tropical climate, the country is particularly susceptible to heatwaves, the frequency and intensity of which have been increasing recently due to various factors.
The Indian Meteorological Department (IMD) has set specific criteria for declaring a heatwave in India. A heatwave is only considered when the maximum temperature reaches at least 40°C for Plains and a minimum of 30°C for hilly regions. Additionally, if the actual maximum temperature remains 45°C or more, irrespective of the normal maximum temperature, a heatwave is declared.
Several significant causes contribute to the occurrence of heatwaves. Foremost among these are global warming, rapid urbanization, lack of pre-monsoon showers, and the El Nino effect.
Global Warming and its Role in Heatwaves
Global warming results from human activities like burning fossil fuels, deforestation, and industrial undertakings leading to long-term increases in Earth’s average temperature. This surge in temperature and changes in weather patterns catalyze heatwaves.
Urbanisation and the Urban Heat Island Effect
The rapid growth of concrete jungles due to urbanization has given rise to the phenomenon known as the “urban heat island effect.” High population density and concrete structures in urban areas absorb and retain more heat, which escalates temperatures during heatwaves.
The El Nino Effect and Sparse Pre-Monsoon Season Showers
El Nino, coupled with weather patterns, often raises temperatures in Asia, leading to record high temperatures. Likewise, less moisture, leaving parts of India arid, and the abrupt end of pre-monsoon rain showers also contributes to heatwaves.
Impacts of Heat Waves
Heatwaves have significant impacts on health, water resources, and energy. Heat cramps, heat exhaustion, heatstroke, and hyperthermia are among the health issues caused by rapid increases in heat gain. Similarly, heatwaves can exacerbate water scarcity issues in India by drying up water bodies, reducing water available for agriculture and domestic use, leading to potential conflicts over water resources. They also increase electricity demand for cooling, causing strain on power grids and possible blackouts.
A Need for Mitigation Strategies
Preventing deaths due to heatwaves is feasible, thus necessitating the government’s priority to prepare a long-term action plan to protect human lives, livestock, and wildlife. A Heat Waves Action Plan could be effective only with the efficient implementation of the Sendai Framework for Disaster Risk Reduction 2015-30. The National Action Plan for Climate Change (NAPCC) must also be implemented for inclusive growth and ecological sustainability, taking nature-based solutions into account.
Sustainable Cooling as A Mitigation Strategy
Passive cooling technology, widely-used to build naturally ventilated buildings, could address the urban heat island effect for residential and commercial structures. The Intergovernmental Panel on Climate Change (IPCC) suggested in its AR6 that ancient Indian building designs employing this technology could be adapted to modern facilities amid global warming.
The UPSC Civil Services Examination previously asked questions on India’s limitations in mitigating global warming and the formation of heat islands in the world’s urban habitat. These make it crucial to understand the causes, effects, and mitigation strategies involved in dealing with heat waves.
